#define  _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int main() {
    int a, b = 0;
    double c = 0;
    while (b < 5)
    {
        scanf("%d", &a);
        if (a <= 100 && a >= 0)
            c += a;
        else
            continue;
        b++;
    }
    printf("%.1lf", c / 5);
    return 0;
}